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title: Data Schema, Context, Ontology
description: Describe the Schema of your data with a set of Semantic Ontologies that will define your JSON-LD Context
layout: ../../../layouts/MainLayout.astro
---

As explained in the previous chapter about the [Semantic Web and Ontologies](/en/framework/semantic), NextGraph is based on RDF, and OWL is used to defined Ontologies, which are equivalent to a Schema definition.